This invention relates to a shower apparatus in which a shower head portion thereof contains an opening valve, a flow adjusting valve and the like and, more particularly, a shower apparatus designed to resist damage by water hammer or the like which may occur when such valve is closed.
General types of shower apparatuses provided in bathrooms contain a shower head connected to a hot water/cold water mixing plug through a hose.
Turning-on and stopping of the water flow is carried out by means of a select handle on a hot water/cold water mixing plug or an opening valve provided in the shower head as disclosed in Japanese Utility Model Publication No. Sho 58-53118.
If the opening valve is suddenly closed in the type in which water feeding and discharge are carried out on the shower head side, water hammer occurs in the primary side of the opening valve, i.e., in a flow route between the hose and the hot water/cold water mixing plug. If water hammer occurs, pressure in the internal flow route rises and at the same time, the pressure changes suddenly. As a result, deterioration in pressure resistance of the hose is induced by vibration of the hose or increase in the internal pressure thereof.
To solve the water hammer problem, it is effective to provide the water plug side with a pressure responding valve or the like for cushioning an increase in the internal pressure as disclosed in Japanese Utility Model Publication No. Sho 58-32753. With the pressure responding valve, a chamber sectioned by a diaphragm is made to communicate with the flow route up to the water discharge device, and the increase in internal pressure which occurs when a valve containing this water discharge device is closed is absorbed by deformation of the diaphragm.
As a mechanism for preventing the aforementioned water hammer phenomenon, various methods are already known, and structures for absorbing or releasing an increase in internal pressure as disclosed in the preceding patent publication are basic ones.
In addition to the above described mechanism for preventing water hammer, as disclosed in Japanese Unexamined Utility Model Publication No. Hei 6-5588, a pressure adjusting valve for adjusting the pressure of mixing water to be fed to the shower head is incorporated in the flow route in the upstream end of the shower hose so that primary side pressure is not applied to the shower hose when the opening valve of the shower head is closed.
If an opening valve for discharging water and stopping thereof is provided, the main body of the shower head is held by one hand and the knob of the opening valve is operated by the other hand. In this case, it is preferable from the viewpoint of usability that operations for stopping the discharge of water, and inverse operations, can be carried out quickly. Thus, a mechanism which opens and closes the flow route all at once by employing a push-button type opening valve is employed so as to quicken valve closure.
If the opening valve closes quickly, the amount of water hammer is increased and the internal pressure on the hose side in the downstream end is changed largely all at once, so that loading of the internal pressure to the hose when water hammer occurs is consistently repeated. It is effective to apply the pressure responding valve as disclosed in the preceding patent publications corresponding to such water hammer.
However, although a diaphragm for absorbing changes in pressure can stabilize pressure in the hose by elastic deformation of the diaphragm even after the pressure responding valve has been closed, the effect thereof in reducing a rise in pressure just after water hammer occurs is limited. Further, if a valve body is provided which is activated to temporarily expand the volume of the internal flow route in correspondence with an increase in pressure, and at the same time close the internal flow route, it is also possible to suppress the increase in pressure which occurs when water hammer occurs. However, after this valve body is moved, response to changes in pressure tend to be inferior to elastic deformation of the diaphragm, so that the effect of stabilizing the pressure in the hose is consequently reduced.
Although the diaphragm type is suitable for stabilization after a change in pressure, the effect of attenuation of an increase in pressure due to water hammer tends to be inferior. On the other hand, although a solid type valve body is preferable for attenuation of rise in pressure, it is not entirely effective for subsequent stabilization of the pressure in the hose. Thus, no conventional types of pressure responding valves using diaphragms or valve bodies are sufficiently effective during the occurrence of water hammer.
For this reason, a type which contains an opening valve in its shower head, even though the pressure responding valve is contained in flow route, is not capable of effectively suppressing an increase in the internal pressure in the hose at the time water flow is stopped. This results in problems, such as accelerated deterioration due to pressure resistance fatigue of the hose.
On the other hand, in a type which contains a pressure adjusting valve in the flow route in the upstream end of the shower hose, when an opening valve provided in the shower head in the form of a hand-operated valve is closed, water hammer occurs in the shower hose, and thereby induces an increase in internal pressure eventually leading to deterioration or damage of the shower hose.
The internal pressure of the shower hose when water is stopped by the hand-operated valve changes variously depending on the closure speed thereof. The value of internal pressure in the shower hose when water is stopped by the hand-held operation on the shower head end is basically determined by a specification of the pressure adjusting valve. However, when the hand-operated valve is closed all at once, the pressure adjusting valve is closed with a high internal pressure in the shower hose because water hammer also occurs, and such high internal pressure is subsequently maintained after valve closure. Thus, load on the shower hose is increased thereby inducing deterioration or damage.
In a type of shower apparatus in which the pressure adjusting valve is improved by reducing its size by combination of the piston and cylinder, hydraulic pressure is sometimes applied in a direction of opening the valve due to a clearance between the piston and the cylinder. Thus, if water is stopped by hand-held operation of a valve on the shower head when the supply water pressure is high, a force keeping the valve of the pressure adjusting valve closed is weakened, and unless the internal pressure in the shower hose is high, it is not possible to stop the supply of water by means of the pressure adjusting valve.
Furthermore, because a function of the pressure adjusting valve is to hold the secondary pressure at a constant value by adjusting an amount of flow to the shower head, the higher the supply pressure on the water supply side, the more the flow route of the pressure adjusting valve is throttled. Thus, if the supply pressure is high, the velocity of flow when water passes through a throttled flow route is increased. If the pressure adjusting valve is closed while this condition is present, a significant water hammer occurs.
Even if the pressure responding valve and the pressure adjusting valve or the like are equipped to prevent occurrence of water hammer as described above, if the feed of water is stopped by the hand-held operation of the valve on the shower head side, a temporary rise of the internal pressure in respective parts including the shower hose is unavoidable.
An object of the present invention is to suppress an increase in pressure due to water hammer which may occur particularly when the feed of water is stopped, in a shower apparatus in which discharge of water and stopping of water is carried out on the shower head side, and thereby reduce pressure applied to respective parts including the shower hose, thereby maintaining continued viability of the parts.